[tip:x86/urgent] x86/acpi: Prevent LAPIC id 0xff from being accounted

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Commit-ID:  cf5b15bf05d416deb6c0bf39bfb634cf5a511b64
Gitweb:     http://git.kernel.org/tip/cf5b15bf05d416deb6c0bf39bfb634cf5a511b64
Author:     Thomas Gleixner <tglx@xxxxxxxxxxxxx>
AuthorDate: Fri, 7 Oct 2016 14:02:12 +0200
Committer:  Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitDate: Sat, 8 Oct 2016 12:07:25 +0200

x86/acpi: Prevent LAPIC id 0xff from being accounted

Yinghai reported that the recent changes to make the cpuid - nodeid
relationship permanent causes a cpuid ordering regression on a system which
has 2apic enabled..

The reason is that the ACPI local APIC parser has no sanity check for
apicid 0xff, which is an invalid id. So a CPU id for this invalid local
APIC id is allocated and therefor breaks the cpuid ordering.

Add a sanity check to acpi_parse_lapic() which ignores the invalid id.

Fixes: 8f54969dc8d6 ("x86/acpi: Introduce persistent storage for cpuid <-> apicid mapping")
Reported-by: Yinghai Lu <yinghai@xxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Gu Zheng <guz.fnst@xxxxxxxxxxxxxx>,
Cc: Tang Chen <tangchen@xxxxxxxxxxxxxx>
Cc: douly.fnst@xxxxxxxxxxxxxx,
Cc: zhugh.fnst@xxxxxxxxxxxxxx
Cc: Tony Luck <tony.luck@xxxxxxxxx>
Cc: Rafael J. Wysocki <rjw@xxxxxxxxxxxxx>
Cc: Len Brown <lenb@xxxxxxxxxx>
Cc: Lv Zheng <lv.zheng@xxxxxxxxx>,
Cc: robert.moore@xxxxxxxxx
Cc: linux-acpi@xxxxxxxxxxxxxxx
Link: https://lkml.kernel.org/r/CAE9FiQVQx6FRXT-RdR7Crz4dg5LeUWHcUSy1KacjR+JgU_vGJg@xxxxxxxxxxxxxx
---
 arch/x86/kernel/acpi/boot.c | 4 ++++
 arch/x86/kernel/apic/apic.c | 8 +++++---
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c
index 32a7d70..8a5abaa 100644
--- a/arch/x86/kernel/acpi/boot.c
+++ b/arch/x86/kernel/acpi/boot.c
@@ -233,6 +233,10 @@ acpi_parse_lapic(struct acpi_subtable_header * header, const unsigned long end)
 
 	acpi_table_print_madt_entry(header);
 
+	/* Ignore invalid ID */
+	if (processor->id == 0xff)
+		return 0;
+
 	/*
 	 * We need to register disabled CPU as well to permit
 	 * counting disabled CPUs. This allows us to size
diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index f266b8a..dc9ec12 100644
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -2128,9 +2128,11 @@ int __generic_processor_info(int apicid, int version, bool enabled)
 	if (num_processors >= nr_cpu_ids) {
 		int thiscpu = max + disabled_cpus;
 
-		pr_warning(
-			"APIC: NR_CPUS/possible_cpus limit of %i reached."
-			"  Processor %d/0x%x ignored.\n", max, thiscpu, apicid);
+		if (enabled) {
+			pr_warn_once("APIC: NR_CPUS/possible_cpus limit of %i "
+				     "reached. Processor %d/0x%x ignored.\n",
+				     max, thiscpu, apicid);
+		}
 
 		disabled_cpus++;
 		return -EINVAL;
--
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